Mascara brushes of the type commonly referred to as “twisted wire” brushes are well known and widely used in the cosmetics industry. A twisted wire mascara brush has an axially elongated twisted wire core with a multiplicity of fibers such as bristles clamped at their midpoints in the core and extending radially outwardly therefrom; the core is constituted of two lengths of wire, which may be initially separate or may be opposed legs of a single U-shaped wire, twisted together into a helix to hold the bristles between them. Typically, the bristles are more or less uniformly distributed for at least most of the length of the brush, and the overall shape of the brush (i.e., the notional envelope defined by the tips of the bristles) has a rectilinear axis and a simple circular cross-section, being cylindrical, frustoconical, or a tandem arrangement of proximal cylindrical and distal frustoconical portions.
Although the combination of a twisted wire core and a radiating array of bristles clamped in the core provides an acceptable brush structure for uses exemplified by the application of mascara, twisted-in-wire mascara brushes have certain disadvantages. One such disadvantage would be the finite number of ways fibres can be used to create an application surface for the mascara while at the same time serving a market continually looking for differentiation. Moreover, a conventional twisted-wire brush offers essentially only one kind of brush profile for use both to transfer the mascara from the container to the face and to apply the mascara to the eye lashes. To enable improved application, it would be beneficial to provide mascara brushes having structures other than uniformly distributed bristle arrays with simple cylindrical and/or conical envelopes of circular cross-section; but the diversity of possible configurations of twisted-in-wire brushes is restricted by the requirement to trim the bristles in order to achieve desired shapes, and the difficulty of forming and positioning cutters to effect such trimming.
It has also been proposed heretofore to employ plastic brushes and combs as mascara applicators.
There nevertheless remains a need for designs affording or permitting enhanced functional versatility (e.g., thickening, lengthening and separation as well as delivery of mascara to the lashes). In particular, there is a need for a mascara design that satisfies two requirements for achieving a pleasing make-up effect on the lashes: first, the retention and application of mascara to the lashes and second, the combing and separation of the lashes to which the mascara has been applied.
Various prior art injection-molded applicators have attempted to satisfy these requirements, using different bristle shapes, as well as a variety of bristle row distributions, densities, etc.
It is known from U.S. Pat. Nos. 4,964,429 and 6,616,366, for example, to arrange teeth in one or more rows extending helically around and along the stem. Such an arrangement, which replicates the distribution of bristles of a traditional twisted wire mascara brush, is known to provide advantageous effects in terms of hair combing and separation.
The amount of mascara retained between the fingers of these applicators has nevertheless found to be insufficient to provide the desired amount of product on the application surface.
Indeed, such brush configurations do not enable a sufficient quantity of cosmetic product to be collected whenever the brush is dipped into the container and especially following withdrawal from the container. The user is therefore forced to repeatedly insert the applicator into the container to load more product which may lead to contamination of the container's supply.
In other cases, if the cosmetic product is more viscous, the brush may be loaded with too great a quantity of mascara. Such an overloaded brush may lead to unwanted effects following application onto the lashes, such as clumping. Furthermore, the excess cosmetic product tends to accumulate onto the brush surface and dry out thereby reducing the separation ability of the brush bristles. Also, the unused cosmetic product trapped between the brush bristles will be reinserted into the container before a next application and therefore will become mixed with the container's supply, increasing the chances of pollution and contamination.
There exists therefore a need for a mascara brush which provides sufficient product retention capabilities.
It is also known to provide adjustable mascara brushes having coating surfaces in which the axial distance between each coating surface is adjustable. Such a mascara brush, described for example in U.S. Pat. No. 3,998,235, allows a user to vary the distance between the coating surfaces by acting upon a helical spring structure which compresses or expands. Unfortunately, with such an applicator, following adjustment, the axial distance of separation between the coating surfaces is constant, that is, the amount of product loaded between each pair of consecutive coating surfaces is the same. A single application effect will therefore be provided when the mascara brush is used.
Therefore, there exists a need for a mascara brush configuration that allows more than one metered quantity of mascara to be retained and applied.